I'd say that is really great shooting off irons at 100 yards! :wink:
I have been using the Hornady 75 grain BTHP, Prvi 75 grain BTHP and the Nosler 77 grain BTHP all in Lake City 5.56mm brass with CCI 400 primers and 25.0 grains of BLC-2 in both my 556s for hunting and target practice and they all perform excellent.
Here is ten shots @ 100 yard prone, no rest or bipod, using 4X power on a Burris XTR 1-4X scope.
These same rounds at 300 yards give about a five inch group too.
I have been using the Hornady 75 grain BTHP, Prvi 75 grain BTHP and the Nosler 77 grain BTHP all in Lake City 5.56mm brass with CCI 400 primers and 25.0 grains of BLC-2 in both my 556s for hunting and target practice and they all perform excellent.
Here is ten shots @ 100 yard prone, no rest or bipod, using 4X power on a Burris XTR 1-4X scope.

These same rounds at 300 yards give about a five inch group too.